“Take that rock over there. It doesn’t seem to be doing much of anything, at least to our gross perception. But at the microlevel it consists of an unimaginable number of atoms connected by springy chemical bonds, all jiggling around at a rate that even our fastest supercomputer might envy. And they are not jiggling at random. The rock’s innards ‘see’ the entire universe by means of the gravitational and electromagnetic signals it is continuously receiving. Such a system can be viewed as an all-purpose information processor, one whose inner dynamics mirror any sequence of mental states that our brains might run through. And where there is information, says panpsychism, there is consciousness. In David Chalmers’s slogan, ‘Experience is information from the inside; physics is information from the outside.’

But the rock doesn’t exert itself as a result of all this ‘thinking.’ Why should it? Its existence, unlike ours, doesn’t depend on the struggle to survive and self-replicate. It is indifferent to the prospect of being pulverized. If you are poetically inclined, you might think of the rock as a purely contemplative being. And you might draw the moral that the universe is, and always has been, saturated with mind, even though we snobbish Darwinian-replicating latecomers are too blinkered to notice.”

I like this citation a lot. After some search I have found the original paper

Putnam has argued that computational functionalism cannot serve as a foundation for the study of the mind, as every ordinary open physical system implements every finite-state automaton. I argue that Putnam’s argument fails, but that it points out the need for a better understanding of the bridge between the theory of computation and the theory of physical systems: the relation of implementation. It also raises questions about the classes of automata that can serve as a basis for understanding the mind. I develop an account of implementation, linked to an appropriate class of automata, such that the requirement that a system implement a given automaton places a very strong constraint on the system. This clears the way for computation to play a central role in the analysis of mind.